R4 Aurora no video signal after storm

Helping my son troubleshoot his PC.  He has a 2012 R4 purchased new.  He says it is no longer under warranty.  He had a lightning storm that knocked out power to his apartment while he was gaming.  He had it on a power strip along with his phone plugged in to the same strip,  After power was restored he could not get a video signal to the monitor.  His phone no longer worked either.  He swapped monitors but didn't work.  We swapped cards, and swapped power suppplies with spares from my R3 I had.  Nothing worked.  We get a POST, but nothing to the monitor, and I mean nothing.  No pre boot loading screen at all....just a black screen  The fans on both cards come on.